mirror of
https://github.com/cc65/cc65.git
synced 2024-12-24 11:31:31 +00:00
1cc4fa9356
Extendend memory is mapped over the main memory in the 0x4000..0x7FFF area. Many DOSes disable interrupts while extended memory is banked in, but not all (e.g. SpartaDOS-X). This change modifies the initial interrupt handler to map in main memory before chaining to the "worker" handlers. Since the initial interrupt handler uses a data segment to store the trampoline to chain to the original handler, introduce a new "LOWBSS" segment to hold this trampoline. Otherwise the trampoline may end up inside the 0x4000..0x7FFF area. Add a link time warning if "LOWCODE" segment lays within the extended memory window.
211 lines
5.3 KiB
ArmAsm
211 lines
5.3 KiB
ArmAsm
;
|
|
; Startup code for cc65 (ATARI version)
|
|
;
|
|
; Contributing authors:
|
|
; Mark Keates
|
|
; Freddy Offenga
|
|
; Christian Groessler
|
|
; Stefan Haubenthal
|
|
;
|
|
|
|
.export __STARTUP__ : absolute = 1 ; Mark as startup
|
|
.export _exit, start, excexit, SP_save
|
|
|
|
.import initlib, donelib
|
|
.import callmain, zerobss
|
|
.import __RESERVED_MEMORY__
|
|
.import __MAIN_START__, __MAIN_SIZE__
|
|
.import __LOWCODE_RUN__, __LOWCODE_SIZE__
|
|
.ifdef __ATARIXL__
|
|
.import __STACKSIZE__
|
|
.import sram_init
|
|
.import scrdev
|
|
.import findfreeiocb
|
|
.forceimport sramprep ; force inclusion of the "shadow RAM preparation" load chunk
|
|
.include "save_area.inc"
|
|
.endif
|
|
|
|
.include "zeropage.inc"
|
|
.include "atari.inc"
|
|
|
|
; ------------------------------------------------------------------------
|
|
|
|
.segment "STARTUP"
|
|
|
|
rts ; fix for SpartaDOS / OS/A+
|
|
; They first call the entry point from AUTOSTRT; and
|
|
; then, the load address (this rts here).
|
|
; We point AUTOSTRT directly after the rts.
|
|
|
|
; Real entry point:
|
|
|
|
start:
|
|
|
|
.ifdef __ATARIXL__
|
|
jsr sram_init
|
|
.endif
|
|
|
|
; Clear the BSS data.
|
|
|
|
jsr zerobss
|
|
|
|
; Set up the stack.
|
|
|
|
tsx
|
|
stx SP_save
|
|
|
|
.ifdef __ATARIXL__
|
|
|
|
lda #<(__MAIN_START__ + __MAIN_SIZE__ + __STACKSIZE__)
|
|
ldx #>(__MAIN_START__ + __MAIN_SIZE__ + __STACKSIZE__)
|
|
sta sp
|
|
stx sp+1
|
|
|
|
.else
|
|
|
|
; Report the memory usage.
|
|
|
|
lda APPMHI
|
|
ldx APPMHI+1
|
|
sta APPMHI_save ; remember old APPMHI value
|
|
stx APPMHI_save+1
|
|
|
|
sec
|
|
lda MEMTOP
|
|
sbc #<__RESERVED_MEMORY__
|
|
sta APPMHI ; initialize our APPMHI value
|
|
sta sp ; set up runtime stack part 1
|
|
lda MEMTOP+1
|
|
sbc #>__RESERVED_MEMORY__
|
|
sta APPMHI+1
|
|
sta sp+1 ; set up runtime stack part 2
|
|
|
|
.endif
|
|
|
|
; Call the module constructors.
|
|
|
|
jsr initlib
|
|
|
|
; Set the left margin to 0.
|
|
|
|
lda LMARGN
|
|
sta LMARGN_save
|
|
ldy #0
|
|
sty LMARGN
|
|
|
|
; Set the keyboard to upper-/lower-case mode.
|
|
|
|
ldx SHFLOK
|
|
stx SHFLOK_save
|
|
sty SHFLOK
|
|
|
|
; Initialize the conio stuff.
|
|
|
|
dey ; Set Y to $FF
|
|
sty CH ; remove keypress which might be in the input buffer
|
|
|
|
; Push the command-line arguments; and, call main().
|
|
|
|
jsr callmain
|
|
|
|
; Call the module destructors. This is also the exit() entry.
|
|
|
|
_exit: ldx SP_save
|
|
txs ; Restore stack pointer
|
|
|
|
; Restore the system stuff.
|
|
|
|
excexit:jsr donelib ; Run module destructors; 'excexit' is called from the exec routine
|
|
|
|
; Restore the left margin.
|
|
|
|
lda LMARGN_save
|
|
sta LMARGN
|
|
|
|
; Restore the kb mode.
|
|
|
|
lda SHFLOK_save
|
|
sta SHFLOK
|
|
|
|
; Restore APPMHI.
|
|
|
|
lda APPMHI_save
|
|
ldx APPMHI_save+1
|
|
sta APPMHI
|
|
stx APPMHI+1
|
|
|
|
.ifdef __ATARIXL__
|
|
|
|
; Atari XL target stuff...
|
|
|
|
lda PORTB_save
|
|
sta PORTB
|
|
lda RAMTOP_save
|
|
sta RAMTOP
|
|
lda MEMTOP_save
|
|
ldx MEMTOP_save+1
|
|
sta MEMTOP
|
|
stx MEMTOP+1
|
|
|
|
|
|
; Issue a GRAPHICS 0 call (copied'n'pasted from the TGI drivers), in
|
|
; order to restore screen memory to its default location just
|
|
; before the ROM.
|
|
|
|
jsr findfreeiocb
|
|
|
|
; Reopen it in Graphics 0
|
|
lda #OPEN
|
|
sta ICCOM,x
|
|
lda #OPNIN | OPNOT
|
|
sta ICAX1,x
|
|
lda #0
|
|
sta ICAX2,x
|
|
lda #<scrdev
|
|
sta ICBAL,x
|
|
lda #>scrdev
|
|
sta ICBAH,x
|
|
lda #3
|
|
sta ICBLL,x
|
|
lda #0
|
|
sta ICBLH,x
|
|
jsr CIOV_org
|
|
; No error checking here, shouldn't happen(TM); and, no way to
|
|
; recover anyway.
|
|
|
|
lda #CLOSE
|
|
sta ICCOM,x
|
|
jsr CIOV_org
|
|
|
|
.endif
|
|
|
|
; Turn on the cursor.
|
|
|
|
ldx #0
|
|
stx CRSINH
|
|
|
|
; Back to DOS.
|
|
|
|
rts
|
|
|
|
; *** end of main startup code
|
|
|
|
; ------------------------------------------------------------------------
|
|
|
|
.bss
|
|
|
|
SP_save: .res 1
|
|
SHFLOK_save: .res 1
|
|
LMARGN_save: .res 1
|
|
.ifndef __ATARIXL__
|
|
APPMHI_save: .res 2
|
|
.endif
|
|
|
|
; ------------------------------------------------------------------------
|
|
|
|
.segment "LOWCODE" ; have at least one (empty) segment of LOWCODE, so that the next line works even if the program doesn't make use of this segment
|
|
.assert (__LOWCODE_RUN__ + __LOWCODE_SIZE__ <= $4000 || __LOWCODE_RUN__ > $7FFF || __LOWCODE_SIZE__ = 0), warning, "'lowcode area' reaches into $4000..$7FFF bank memory window"
|
|
; check for LOWBSS_SIZE = 0 not needed since the only file which uses LOWBSS (irq.s) also uses LOWCODE
|
|
; check for LOWCODE_RUN > $7FFF is mostly for cartridges, where this segment is loaded high (into cart ROM)
|
|
; there is a small chance that if the user loads the program really high, LOWCODE is above $7FFF, but LOWBSS is below -- no warning emitted in this case
|